pg_fetch_result

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

pg_fetch_result — 从结果实例返回值

说明

pg_fetch_result(PgSql\Result $result, string|false|null $row, mixed $field): string|false|null

pg_fetch_result(PgSql\Result $result, mixed $field): string|false|null

pg_fetch_result() 返回 PgSql\Result 实例中特定行和字段（列）的值。

注意:
此函数过去称为 pg_result()。

参数

result: PgSql\Result 实例，由 pg_query()、pg_query_params() 或者 pg_execute()（等）返回。
row: 要获取的结果中的行号。行从 0 向上编号。如果省略，则获取下一行。
field: 表示要获取的字段（列）名的 string，否则为表示要获取的字段编号的 int。字段从 0 向上编号。

返回值

布尔值返回为 "t" 或 "f"。所有其它类型，包括数组，都以字符串形式返回，其格式与 psql 程序中的 PostgreSQL 默认方式相同。数据库 NULL 值作为 null 返回。

如果 row 超过集合中的行数或任何其他错误，则返回 false。

更新日志

版本	说明
8.3.0	`row` 现在可为 null。
8.1.0	现在 `result` 参数接受 PgSql\Result 实例，之前接受 resource。

示例

示例 #1 pg_fetch_result() 示例

<?php
$db = pg_connect("dbname=users user=me") || die();

$res = pg_query($db, "SELECT 1 UNION ALL SELECT 2");

$val = pg_fetch_result($res, 1, 0);

echo "First field in the second row is: ", $val, "\n";
?>

以上示例会输出：

First field in the second row is: 2

参见

pg_query() - 执行查询
pg_fetch_array() - 获取一行作为数组

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用户贡献的备注 5 notes

down

ElDiablo ¶

6 years ago

Please note that a very old bug (#76548) has been fixed in 7.2.8.

Previously, pg_fetch_result did not fetch the next row if $row was omitted.
It is now well the case, so bad use of the function can now cause some bugs in your codes.

down

newby_AT_nobletec_DOT_com ¶

22 years ago

Comment on boolean fields:

If you retrieve a boolean value from the PostgreSQL database, be aware that the value returned will be either the character 't' or the character 'f', not an integer.  So, the statement

     if (pg_fetch_result($rsRecords,0,'blnTrueFalseField')) {
       echo "TRUE";
     } else {
       echo "FALSE";
     }

will echo "TRUE" in either case (True or False stored in the field).  In order to work as expected, do this instead:

     if (pg_fetch_result($rsRecords,0,'blnTrueFalseField') == 't') {
       echo "TRUE";
     } else {
       echo "FALSE";
     }

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Alan U. Kennington ¶

18 years ago

See bug #33809 http://bugs.php.net/bug.php?id=33809
Whether this really is a bug or a feature is not clear.
However, it is probably best to always put your column names in extra quotes.

$res = pg_query(...);
$colname = pg_field_name($res, $j);
pg_fetch_result($res, $i, "\"$colname\"");

down

-2

Alan U Kennington ¶

18 years ago

In order to use upper case in pg_fetch_result column names, it is apparently necessary to include explicit quotation marks.

Thus when I do this sort of thing:

$res = pg_query(...);
$ncols = pg_num_fields($res);
for ($j = 0; $j < $ncols; ++$j) {
    $colname[$j] = pg_field_name($res, $j);
    $name = htmlspecialchars($colname[$j]);
    print("Column $j name = \"$name\"\n");
    $value = htmlspecialchars(pg_fetch_result($res, 0, $colname[$j]));
    print("Column \"{$colname[$j]}\" value = \"$value\"\n");
    }

I get this sort of thing:

[....]
Warning: pg_fetch_result() [function.pg-fetch-result]: Bad column offset specified in /.../view.php on line 247
Column 8 name = "VEC index"
Column "VEC index" value = ""

But if I change the $value line to this:

$value = htmlspecialchars(pg_fetch_result($res, 0, "\"$colname[$j]\""));

I get this:

[...]
Column 8 name = "VEC index"
Column "VEC index" value[0] = "47"

In my opinion, pg_fetch_result(...) should use the quotes already. In other words, this may be a bug in the PHP postgres library. It does not seem to be a documented feature of pg_fetch_result() although the postgresql manual documents it under "SQL syntax", "Lexical structure".

PHP version 5.1.4.
psql version 8.1.4.

down

-3

Akbar ¶

19 years ago

Use can use pg_fetch_result when getting a value (like a smallint as in this example) returned by your stored procedure 

<?php
$pgConnection = pg_connect("dbname=users user=me");

$userNameToCheckFor = "metal";

$result = pg_query($pgConnection, "SELECT howManyUsersHaveThisName('$userNameToCheckFor')");

$count = pg_fetch_result($result, 0, 'howManyUsersHaveThisName');

?>